1. Field of the Invention
The present invention relates to a stripping device and a stripping apparatus including the stripping device for stripping a supporting plate from a substrate such as a semiconductor wafer to be used when the substrate is thinned.
2. Description of the Background Art
There is a continuing need to make IC cards and cell phones thinner, smaller, and lighter. In order to satisfy this need, semiconductor chips to be incorporated therein must be thin. Although at present the thickness of a wafer which forms a semiconductor chip is 125-150 μm, it is expected that the thickness of a semiconductor wafer must be 25-50 μm for a next generation of chips.
An example of a conventional method for thinning a semiconductor wafer is shown in FIG. 11.
Specifically, a supporting plate or a protecting tape is attached to a surface (A-surface) of a semiconductor wafer on which a circuit (element) has been formed. This is turned over, and the rear surface (B-surface) of the semiconductor wafer is ground by a grinder to make the wafer thinner. Another circuit is formed on the rear surface (B-surface) of the semiconductor wafer which has been thinned, and this is fixed onto a dicing tape retained by a dicing frame. The supporting plate or the protecting tape covering the surface (A-surface) of the semiconductor wafer is stripped in this state. Next, the wafer is cut into chips by a dicing device (See Document 1).
[Document 1] Japanese Patent Application Publication No. 2002-270676
The present inventors have filed an application with respect to a method for stripping a supporting plate from a semiconductor wafer. This method is performed by using a plate in which a first penetrating hole is formed in a central portion of the plate in the thickness direction and a second penetrating hole is formed in a peripheral portion of the plate in the thickness direction.
Specifically, as shown in FIGS. 12a and 12b, a plate 60 is applied to a supporting plate 64 of a layered structure in which the supporting plate 64 has been attached to a semiconductor wafer W in a state where an O-ring 61 is interposed. Next, a solvent is supplied to a space formed by the O-ring 61 through a central penetrating hole 62 so as to distribute the solvent over an adhesive layer 65 through the penetrating hole of the supporting plate 64. In this way, the adhesive layer 65 is dissolved by the solvent. The solvent is withdrawn from a peripheral penetrating hole 63 of the plate 60.
In this stripping method, however, the solvent is supplied from above with respect to the plate 60 and the layered structure. Therefore, in order to withdraw the solvent from the periphery of the plate 60, the solvent needs to be sucked. Therefore, a sucking device is required, and an extra space is required for this additional device.
Also, if the solvent leaks from around the O-ring 61, the solvent reaches a dicing tape 67 of a dicing frame 66, which results in stripping of the dicing tape 67 from the layered structure.
In order to solve this drawback, it is possible to supply the solvent from below with respect to the plate 60. In this instance, however, the layered structure needs to be rotated by a rotating device so as to locate the supporting plate on the plate side (i.e., mount the layered structure on the plate) at the time of transferring the layered structure from a transfer robot to a stripping apparatus. Therefore, extra space is required for this additional device, and the stripping process takes longer because additional time is required for transferring the layered structure between the devices.
In order to solve the above-mentioned problems, an object of the present invention is to provide a stripping device and a stripping apparatus including the stripping device which make it possible to simplify a structure of the apparatus for stripping a supporting plate from a layered structure, reduce the space for the apparatus, and also reduce the time required for stripping the supporting plate.